/* expr.c -operands, expressions- Copyright (C) 1987, 1990, 1991, 1992 Free Software Foundation, Inc. This file is part of GAS, the GNU Assembler. GAS is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2, or (at your option) any later version. GAS is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with GAS; see the file COPYING. If not, write to the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */ /* * This is really a branch office of as-read.c. I split it out to clearly * distinguish the world of expressions from the world of statements. * (It also gives smaller files to re-compile.) * Here, "operand"s are of expressions, not instructions. */ #ifndef lint static char rcsid[] = "$FreeBSD$"; #endif #include #include #include "as.h" #include "obstack.h" #if __STDC__ == 1 static void clean_up_expression(expressionS *expressionP); #else /* __STDC__ */ static void clean_up_expression(); /* Internal. */ #endif /* not __STDC__ */ extern const char EXP_CHARS[]; /* JF hide MD floating pt stuff all the same place */ extern const char FLT_CHARS[]; #ifdef LOCAL_LABELS_DOLLAR extern int local_label_defined[]; #endif /* * Build any floating-point literal here. * Also build any bignum literal here. */ /* LITTLENUM_TYPE generic_buffer[6]; */ /* JF this is a hack */ /* Seems atof_machine can backscan through generic_bignum and hit whatever happens to be loaded before it in memory. And its way too complicated for me to fix right. Thus a hack. JF: Just make generic_bignum bigger, and never write into the early words, thus they'll always be zero. I hate Dean's floating-point code. Bleh. */ LITTLENUM_TYPE generic_bignum[SIZE_OF_LARGE_NUMBER+6]; FLONUM_TYPE generic_floating_point_number = { &generic_bignum[6], /* low (JF: Was 0) */ &generic_bignum[SIZE_OF_LARGE_NUMBER+6 - 1], /* high JF: (added +6) */ 0, /* leader */ 0, /* exponent */ 0 /* sign */ }; /* If nonzero, we've been asked to assemble nan, +inf or -inf */ int generic_floating_point_magic; /* * Summary of operand(). * * in: Input_line_pointer points to 1st char of operand, which may * be a space. * * out: A expressionS. X_seg determines how to understand the rest of the * expressionS. * The operand may have been empty: in this case X_seg == SEG_ABSENT. * Input_line_pointer->(next non-blank) char after operand. * */ static segT operand (expressionP) register expressionS * expressionP; { register char c; register char *name; /* points to name of symbol */ register symbolS * symbolP; /* Points to symbol */ extern const char hex_value[]; /* In hex_value.c */ #ifdef PIC /* XXX */ expressionP->X_got_symbol = 0; #endif SKIP_WHITESPACE(); /* Leading whitespace is part of operand. */ c = * input_line_pointer ++; /* Input_line_pointer->past char in c. */ if (isdigit(c) || (c == 'H' && input_line_pointer[0] == '\'')) { register valueT number; /* offset or (absolute) value */ register short int digit; /* value of next digit in current radix */ /* invented for humans only, hope */ /* optimising compiler flushes it! */ register short int radix; /* 2, 8, 10 or 16 */ /* 0 means we saw start of a floating- */ /* point constant. */ register short int maxdig = 0;/* Highest permitted digit value. */ register int too_many_digits = 0; /* If we see >= this number of */ /* digits, assume it is a bignum. */ register char * digit_2; /*->2nd digit of number. */ int small; /* TRUE if fits in 32 bits. */ if (c == 'H' || c == '0') { /* non-decimal radix */ if ((c = *input_line_pointer ++) == 'x' || c == 'X' || c == '\'') { c = *input_line_pointer ++; /* read past "0x" or "0X" or H' */ maxdig = radix = 16; too_many_digits = 9; } else { /* If it says '0f' and the line ends or it DOESN'T look like a floating point #, its a local label ref. DTRT */ /* likewise for the b's. xoxorich. */ if ((c == 'f' || c == 'b' || c == 'B') && (!*input_line_pointer || (!strchr("+-.0123456789iInN",*input_line_pointer) && !strchr(EXP_CHARS,*input_line_pointer)))) { maxdig = radix = 10; too_many_digits = 11; c = '0'; input_line_pointer -= 2; } else if (c == 'b' || c == 'B') { c = *input_line_pointer++; maxdig = radix = 2; too_many_digits = 33; } else if (c && strchr(FLT_CHARS,c)) { radix = 0; /* Start of floating-point constant. */ /* input_line_pointer->1st char of number. */ expressionP->X_add_number = -(isupper(c) ? tolower(c) : c); } else { /* By elimination, assume octal radix. */ radix = maxdig = 8; too_many_digits = 11; } } /* c == char after "0" or "0x" or "0X" or "0e" etc. */ } else { maxdig = radix = 10; too_many_digits = 11; } /* if operand starts with a zero */ if (radix) { /* Fixed-point integer constant. */ /* May be bignum, or may fit in 32 bits. */ /* * Most numbers fit into 32 bits, and we want this case to be fast. * So we pretend it will fit into 32 bits. If, after making up a 32 * bit number, we realise that we have scanned more digits than * comfortably fit into 32 bits, we re-scan the digits coding * them into a bignum. For decimal and octal numbers we are conservative: some * numbers may be assumed bignums when in fact they do fit into 32 bits. * Numbers of any radix can have excess leading zeros: we strive * to recognise this and cast them back into 32 bits. * We must check that the bignum really is more than 32 * bits, and change it back to a 32-bit number if it fits. * The number we are looking for is expected to be positive, but * if it fits into 32 bits as an unsigned number, we let it be a 32-bit * number. The cavalier approach is for speed in ordinary cases. */ digit_2 = input_line_pointer; for (number=0; (digit=hex_value[c])char after C. */ small = input_line_pointer - digit_2 < too_many_digits; if (!small) { /* * We saw a lot of digits. Manufacture a bignum the hard way. */ LITTLENUM_TYPE *leader; /*->high order littlenum of the bignum. */ LITTLENUM_TYPE *pointer; /*->littlenum we are frobbing now. */ long carry; leader = generic_bignum; generic_bignum[0] = 0; generic_bignum[1] = 0; /* We could just use digit_2, but lets be mnemonic. */ input_line_pointer = --digit_2; /*->1st digit. */ c = *input_line_pointer++; for (; (carry = hex_value[c]) < maxdig; c = *input_line_pointer++) { for (pointer = generic_bignum; pointer <= leader; pointer++) { long work; work = carry + radix * *pointer; *pointer = work & LITTLENUM_MASK; carry = work >> LITTLENUM_NUMBER_OF_BITS; } if (carry) { if (leader < generic_bignum + SIZE_OF_LARGE_NUMBER - 1) { /* Room to grow a longer bignum. */ *++leader = carry; } } } /* Again, C is char after number, */ /* input_line_pointer->after C. */ know(sizeof (int) * 8 == 32); know(LITTLENUM_NUMBER_OF_BITS == 16); /* Hence the constant "2" in the next line. */ if (leader < generic_bignum + 2) { /* Will fit into 32 bits. */ number = ((generic_bignum[1] & LITTLENUM_MASK) << LITTLENUM_NUMBER_OF_BITS) | (generic_bignum[0] & LITTLENUM_MASK); small = 1; } else { number = leader - generic_bignum + 1; /* Number of littlenums in the bignum. */ } } if (small) { /* * Here with number, in correct radix. c is the next char. * Note that unlike Un*x, we allow "011f" "0x9f" to * both mean the same as the (conventional) "9f". This is simply easier * than checking for strict canonical form. Syntax sux! */ if (number<10) { if (0 #ifdef LOCAL_LABELS_FB || c == 'b' #endif #ifdef LOCAL_LABELS_DOLLAR || (c == '$' && local_label_defined[number]) #endif ) { /* * Backward ref to local label. * Because it is backward, expect it to be DEFINED. */ /* * Construct a local label. */ name = local_label_name ((int)number, 0); if (((symbolP = symbol_find(name)) != NULL) /* seen before */ && (S_IS_DEFINED(symbolP))) /* symbol is defined: OK */ { /* Expected path: symbol defined. */ /* Local labels are never absolute. Don't waste time checking absoluteness. */ know(SEG_NORMAL(S_GET_SEGMENT(symbolP))); expressionP->X_add_symbol = symbolP; expressionP->X_add_number = 0; expressionP->X_seg = S_GET_SEGMENT(symbolP); } else { /* Either not seen or not defined. */ as_bad("Backw. ref to unknown label \"%d:\", 0 assumed.", number); expressionP->X_add_number = 0; expressionP->X_seg = SEG_ABSOLUTE; } } else { if (0 #ifdef LOCAL_LABELS_FB || c == 'f' #endif #ifdef LOCAL_LABELS_DOLLAR || (c == '$' && !local_label_defined[number]) #endif ) { /* * Forward reference. Expect symbol to be undefined or * unknown. Undefined: seen it before. Unknown: never seen * it in this pass. * Construct a local label name, then an undefined symbol. * Don't create a XSEG frag for it: caller may do that. * Just return it as never seen before. */ name = local_label_name((int)number, 1); symbolP = symbol_find_or_make(name); /* We have no need to check symbol properties. */ #ifndef MANY_SEGMENTS /* Since "know" puts its arg into a "string", we can't have newlines in the argument. */ know(S_GET_SEGMENT(symbolP) == SEG_UNKNOWN || S_GET_SEGMENT(symbolP) == SEG_TEXT || S_GET_SEGMENT(symbolP) == SEG_DATA); #endif expressionP->X_add_symbol = symbolP; expressionP->X_seg = SEG_UNKNOWN; expressionP->X_subtract_symbol = NULL; expressionP->X_add_number = 0; } else { /* Really a number, not a local label. */ expressionP->X_add_number = number; expressionP->X_seg = SEG_ABSOLUTE; input_line_pointer--; /* Restore following character. */ } /* if (c == 'f') */ } /* if (c == 'b') */ } else { /* Really a number. */ expressionP->X_add_number = number; expressionP->X_seg = SEG_ABSOLUTE; input_line_pointer--; /* Restore following character. */ } /* if (number<10) */ } else { expressionP->X_add_number = number; expressionP->X_seg = SEG_BIG; input_line_pointer --; /*->char following number. */ } /* if (small) */ } /* (If integer constant) */ else { /* input_line_pointer->*/ /* floating-point constant. */ int error_code; error_code = atof_generic (& input_line_pointer, ".", EXP_CHARS, & generic_floating_point_number); if (error_code) { if (error_code == ERROR_EXPONENT_OVERFLOW) { as_bad("Bad floating-point constant: exponent overflow, probably assembling junk"); } else { as_bad("Bad floating-point constant: unknown error code=%d.", error_code); } } expressionP->X_seg = SEG_BIG; /* input_line_pointer->just after constant, */ /* which may point to whitespace. */ know(expressionP->X_add_number < 0); /* < 0 means "floating point". */ } /* if (not floating-point constant) */ } else if (c == '.' && !is_part_of_name(*input_line_pointer)) { extern struct obstack frags; /* JF: '.' is pseudo symbol with value of current location in current segment... */ symbolP = symbol_new("\001L0", now_seg, (valueT)(obstack_next_free(&frags)-frag_now->fr_literal), frag_now); expressionP->X_add_number=0; expressionP->X_add_symbol=symbolP; expressionP->X_seg = now_seg; } else if (is_name_beginner(c)) { /* here if did not begin with a digit */ /* * Identifier begins here. * This is kludged for speed, so code is repeated. */ name = input_line_pointer - 1; c = get_symbol_end(); symbolP = symbol_find_or_make(name); /* * If we have an absolute symbol or a reg, then we know its value now. */ expressionP->X_seg = S_GET_SEGMENT(symbolP); switch (expressionP->X_seg) { case SEG_ABSOLUTE: case SEG_REGISTER: expressionP->X_add_number = S_GET_VALUE(symbolP); break; default: expressionP->X_add_number = 0; #ifdef PIC if (symbolP == GOT_symbol) { expressionP->X_got_symbol = symbolP; got_referenced = 1; } else #endif expressionP->X_add_symbol = symbolP; } *input_line_pointer = c; expressionP->X_subtract_symbol = NULL; } else if (c == '(' || c == '[') {/* didn't begin with digit & not a name */ (void)expression(expressionP); /* Expression() will pass trailing whitespace */ if (c == '(' && *input_line_pointer++ != ')' || c == '[' && *input_line_pointer++ != ']') { as_bad("Missing ')' assumed"); input_line_pointer--; } /* here with input_line_pointer->char after "(...)" */ } else if (c == '~' || c == '-' || c == '+') { /* unary operator: hope for SEG_ABSOLUTE */ switch (operand (expressionP)) { case SEG_ABSOLUTE: /* input_line_pointer->char after operand */ if (c == '-') { expressionP->X_add_number = - expressionP->X_add_number; /* * Notice: '-' may overflow: no warning is given. This is compatible * with other people's assemblers. Sigh. */ } else if (c == '~') { expressionP->X_add_number = ~ expressionP->X_add_number; } else if (c != '+') { know(0); } /* switch on unary operator */ break; default: /* unary on non-absolute is unsuported */ if (!SEG_NORMAL(operand(expressionP))) { as_bad("Unary operator %c ignored because bad operand follows", c); break; } /* Fall through for normal segments ****/ case SEG_PASS1: case SEG_UNKNOWN: if (c == '-') { /* JF I hope this hack works */ expressionP->X_subtract_symbol=expressionP->X_add_symbol; expressionP->X_add_symbol=0; expressionP->X_seg=SEG_DIFFERENCE; break; } /* Expression undisturbed from operand(). */ } } else if (c == '\'') { /* * Warning: to conform to other people's assemblers NO ESCAPEMENT is permitted * for a single quote. The next character, parity errors and all, is taken * as the value of the operand. VERY KINKY. */ expressionP->X_add_number = * input_line_pointer ++; expressionP->X_seg = SEG_ABSOLUTE; } else { /* can't imagine any other kind of operand */ expressionP->X_seg = SEG_ABSENT; input_line_pointer --; md_operand (expressionP); } /* * It is more 'efficient' to clean up the expressions when they are created. * Doing it here saves lines of code. */ clean_up_expression(expressionP); SKIP_WHITESPACE(); /*->1st char after operand. */ know(*input_line_pointer != ' '); return(expressionP->X_seg); } /* operand() */ /* Internal. Simplify a struct expression for use by expr() */ /* * In: address of a expressionS. * The X_seg field of the expressionS may only take certain values. * Now, we permit SEG_PASS1 to make code smaller & faster. * Elsewise we waste time special-case testing. Sigh. Ditto SEG_ABSENT. * Out: expressionS may have been modified: * 'foo-foo' symbol references cancelled to 0, * which changes X_seg from SEG_DIFFERENCE to SEG_ABSOLUTE; * Unused fields zeroed to help expr(). */ static void clean_up_expression (expressionP) register expressionS *expressionP; { switch (expressionP->X_seg) { case SEG_ABSENT: case SEG_PASS1: expressionP->X_add_symbol = NULL; expressionP->X_subtract_symbol = NULL; expressionP->X_add_number = 0; break; case SEG_BIG: case SEG_ABSOLUTE: expressionP->X_subtract_symbol = NULL; expressionP->X_add_symbol = NULL; break; case SEG_UNKNOWN: expressionP->X_subtract_symbol = NULL; break; case SEG_DIFFERENCE: /* * It does not hurt to 'cancel' NULL == NULL * when comparing symbols for 'eq'ness. * It is faster to re-cancel them to NULL * than to check for this special case. */ if (expressionP->X_subtract_symbol == expressionP->X_add_symbol || (expressionP->X_subtract_symbol && expressionP->X_add_symbol && expressionP->X_subtract_symbol->sy_frag == expressionP->X_add_symbol->sy_frag && S_GET_VALUE(expressionP->X_subtract_symbol) == S_GET_VALUE(expressionP->X_add_symbol))) { expressionP->X_subtract_symbol = NULL; expressionP->X_add_symbol = NULL; expressionP->X_seg = SEG_ABSOLUTE; } break; case SEG_REGISTER: expressionP->X_add_symbol = NULL; expressionP->X_subtract_symbol = NULL; break; default: if (SEG_NORMAL(expressionP->X_seg)) { expressionP->X_subtract_symbol = NULL; } else { BAD_CASE (expressionP->X_seg); } break; } } /* clean_up_expression() */ /* * expr_part () * * Internal. Made a function because this code is used in 2 places. * Generate error or correct X_?????_symbol of expressionS. */ /* * symbol_1 += symbol_2 ... well ... sort of. */ static segT expr_part (symbol_1_PP, symbol_2_P) symbolS ** symbol_1_PP; symbolS * symbol_2_P; { segT return_value; #ifndef MANY_SEGMENTS know((* symbol_1_PP) == NULL || (S_GET_SEGMENT(*symbol_1_PP) == SEG_TEXT) || (S_GET_SEGMENT(*symbol_1_PP) == SEG_DATA) || (S_GET_SEGMENT(*symbol_1_PP) == SEG_BSS) || (!S_IS_DEFINED(* symbol_1_PP))); know(symbol_2_P == NULL || (S_GET_SEGMENT(symbol_2_P) == SEG_TEXT) || (S_GET_SEGMENT(symbol_2_P) == SEG_DATA) || (S_GET_SEGMENT(symbol_2_P) == SEG_BSS) || (!S_IS_DEFINED(symbol_2_P))); #endif if (* symbol_1_PP) { if (!S_IS_DEFINED(* symbol_1_PP)) { if (symbol_2_P) { return_value = SEG_PASS1; * symbol_1_PP = NULL; } else { know(!S_IS_DEFINED(* symbol_1_PP)); return_value = SEG_UNKNOWN; } } else { if (symbol_2_P) { if (!S_IS_DEFINED(symbol_2_P)) { * symbol_1_PP = NULL; return_value = SEG_PASS1; } else { /* {seg1} - {seg2} */ as_bad("Expression too complex, 2 symbols forgotten: \"%s\" \"%s\"", S_GET_NAME(* symbol_1_PP), S_GET_NAME(symbol_2_P)); * symbol_1_PP = NULL; return_value = SEG_ABSOLUTE; } } else { return_value = S_GET_SEGMENT(* symbol_1_PP); } } } else { /* (* symbol_1_PP) == NULL */ if (symbol_2_P) { * symbol_1_PP = symbol_2_P; return_value = S_GET_SEGMENT(symbol_2_P); } else { * symbol_1_PP = NULL; return_value = SEG_ABSOLUTE; } } #ifndef MANY_SEGMENTS know(return_value == SEG_ABSOLUTE || return_value == SEG_TEXT || return_value == SEG_DATA || return_value == SEG_BSS || return_value == SEG_UNKNOWN || return_value == SEG_PASS1); #endif know((*symbol_1_PP) == NULL || (S_GET_SEGMENT(*symbol_1_PP) == return_value)); return (return_value); } /* expr_part() */ void ps (s) symbolS *s; { fprintf (stdout, "%s type %s%s", S_GET_NAME(s), S_IS_EXTERNAL(s) ? "EXTERNAL " : "", segment_name(S_GET_SEGMENT(s))); } void pe (e) expressionS *e; { fprintf (stdout, " segment %s\n", segment_name (e->X_seg)); fprintf (stdout, " add_number %d (%x)\n", e->X_add_number, e->X_add_number); if (e->X_add_symbol) { fprintf (stdout, " add_symbol "); ps (e->X_add_symbol); fprintf (stdout, "\n"); } if (e->X_subtract_symbol) { fprintf (stdout, " sub_symbol "); ps (e->X_subtract_symbol); fprintf (stdout, "\n"); } } /* Expression parser. */ /* * We allow an empty expression, and just assume (absolute,0) silently. * Unary operators and parenthetical expressions are treated as operands. * As usual, Q == quantity == operand, O == operator, X == expression mnemonics. * * We used to do a aho/ullman shift-reduce parser, but the logic got so * warped that I flushed it and wrote a recursive-descent parser instead. * Now things are stable, would anybody like to write a fast parser? * Most expressions are either register (which does not even reach here) * or 1 symbol. Then "symbol+constant" and "symbol-symbol" are common. * So I guess it doesn't really matter how inefficient more complex expressions * are parsed. * * After expr(RANK,resultP) input_line_pointer->operator of rank <= RANK. * Also, we have consumed any leading or trailing spaces (operand does that) * and done all intervening operators. */ typedef enum { O_illegal, /* (0) what we get for illegal op */ O_multiply, /* (1) * */ O_divide, /* (2) / */ O_modulus, /* (3) % */ O_left_shift, /* (4) < */ O_right_shift, /* (5) > */ O_bit_inclusive_or, /* (6) | */ O_bit_or_not, /* (7) ! */ O_bit_exclusive_or, /* (8) ^ */ O_bit_and, /* (9) & */ O_add, /* (10) + */ O_subtract /* (11) - */ } operatorT; #define __ O_illegal static const operatorT op_encoding[256] = { /* maps ASCII->operators */ __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, O_bit_or_not, __, __, __, O_modulus, O_bit_and, __, __, __, O_multiply, O_add, __, O_subtract, __, O_divide, __, __, __, __, __, __, __, __, __, __, __, __, O_left_shift, __, O_right_shift, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, O_bit_exclusive_or, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, O_bit_inclusive_or, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __, __ }; /* * Rank Examples * 0 operand, (expression) * 1 + - * 2 & ^ ! | * 3 * / % << >> */ static const operator_rankT op_rank[] = { 0, 3, 3, 3, 3, 3, 2, 2, 2, 2, 1, 1 }; /* Return resultP->X_seg. */ segT expr(rank, resultP) register operator_rankT rank; /* Larger # is higher rank. */ register expressionS *resultP; /* Deliver result here. */ { expressionS right; register operatorT op_left; register char c_left; /* 1st operator character. */ register operatorT op_right; register char c_right; know(rank >= 0); (void) operand(resultP); know(*input_line_pointer != ' '); /* Operand() gobbles spaces. */ c_left = *input_line_pointer; /* Potential operator character. */ op_left = op_encoding[c_left]; while (op_left != O_illegal && op_rank[(int) op_left] > rank) { input_line_pointer++; /*->after 1st character of operator. */ /* Operators "<<" and ">>" have 2 characters. */ if (*input_line_pointer == c_left && (c_left == '<' || c_left == '>')) { input_line_pointer ++; } /*->after operator. */ if (SEG_ABSENT == expr (op_rank[(int) op_left], &right)) { as_warn("Missing operand value assumed absolute 0."); resultP->X_add_number = 0; resultP->X_subtract_symbol = NULL; resultP->X_add_symbol = NULL; resultP->X_seg = SEG_ABSOLUTE; } know(*input_line_pointer != ' '); c_right = *input_line_pointer; op_right = op_encoding[c_right]; if (*input_line_pointer == c_right && (c_right == '<' || c_right == '>')) { input_line_pointer ++; } /*->after operator. */ know((int) op_right == 0 || op_rank[(int) op_right] <= op_rank[(int) op_left]); /* input_line_pointer->after right-hand quantity. */ /* left-hand quantity in resultP */ /* right-hand quantity in right. */ /* operator in op_left. */ if (resultP->X_seg == SEG_PASS1 || right.X_seg == SEG_PASS1) { resultP->X_seg = SEG_PASS1; } else { if (resultP->X_seg == SEG_BIG) { as_warn("Left operand of %c is a %s. Integer 0 assumed.", c_left, resultP->X_add_number > 0 ? "bignum" : "float"); resultP->X_seg = SEG_ABSOLUTE; resultP->X_add_symbol = 0; resultP->X_subtract_symbol = 0; resultP->X_add_number = 0; } if (right.X_seg == SEG_BIG) { as_warn("Right operand of %c is a %s. Integer 0 assumed.", c_left, right.X_add_number > 0 ? "bignum" : "float"); right.X_seg = SEG_ABSOLUTE; right.X_add_symbol = 0; right.X_subtract_symbol = 0; right.X_add_number = 0; } if (op_left == O_subtract) { /* * Convert - into + by exchanging symbols and negating number. * I know -infinity can't be negated in 2's complement: * but then it can't be subtracted either. This trick * does not cause any further inaccuracy. */ register symbolS * symbolP; right.X_add_number = - right.X_add_number; symbolP = right.X_add_symbol; right.X_add_symbol = right.X_subtract_symbol; right.X_subtract_symbol = symbolP; if (symbolP) { right.X_seg = SEG_DIFFERENCE; } op_left = O_add; } if (op_left == O_add) { segT seg1; segT seg2; #ifndef MANY_SEGMENTS know(resultP->X_seg == SEG_DATA || resultP->X_seg == SEG_TEXT || resultP->X_seg == SEG_BSS || resultP->X_seg == SEG_UNKNOWN || resultP->X_seg == SEG_DIFFERENCE || resultP->X_seg == SEG_ABSOLUTE || resultP->X_seg == SEG_PASS1); know(right.X_seg == SEG_DATA || right.X_seg == SEG_TEXT || right.X_seg == SEG_BSS || right.X_seg == SEG_UNKNOWN || right.X_seg == SEG_DIFFERENCE || right.X_seg == SEG_ABSOLUTE || right.X_seg == SEG_PASS1); #endif clean_up_expression(& right); clean_up_expression(resultP); #ifdef PIC /* XXX - kludge here to accomodate "_GLOBAL_OFFSET_TABLE + (x - y)" * expressions: this only works for this special case, the * _GLOBAL_OFFSET_TABLE thing *must* be the left operand, the whole * expression is given the segment of right expression (always a DIFFERENCE, * which should get resolved by fixup_segment()) */ if (resultP->X_got_symbol) { resultP->X_add_symbol = right.X_add_symbol; resultP->X_subtract_symbol = right.X_subtract_symbol; seg1 = S_GET_SEGMENT(right.X_add_symbol); seg2 = S_GET_SEGMENT(right.X_subtract_symbol); resultP->X_seg = right.X_seg; } else { #endif seg1 = expr_part(&resultP->X_add_symbol, right.X_add_symbol); seg2 = expr_part(&resultP->X_subtract_symbol, right.X_subtract_symbol); #ifdef PIC } #endif if (seg1 == SEG_PASS1 || seg2 == SEG_PASS1) { need_pass_2 = 1; resultP->X_seg = SEG_PASS1; } else if (seg2 == SEG_ABSOLUTE) resultP->X_seg = seg1; else if (seg1 != SEG_UNKNOWN && seg1 != SEG_ABSOLUTE && seg2 != SEG_UNKNOWN && seg1 != seg2) { know(seg2 != SEG_ABSOLUTE); know(resultP->X_subtract_symbol); #ifndef MANY_SEGMENTS know(seg1 == SEG_TEXT || seg1 == SEG_DATA || seg1 == SEG_BSS); know(seg2 == SEG_TEXT || seg2 == SEG_DATA || seg2 == SEG_BSS); #endif know(resultP->X_add_symbol); know(resultP->X_subtract_symbol); as_bad("Expression too complex: forgetting %s - %s", S_GET_NAME(resultP->X_add_symbol), S_GET_NAME(resultP->X_subtract_symbol)); resultP->X_seg = SEG_ABSOLUTE; /* Clean_up_expression() will do the rest. */ } else resultP->X_seg = SEG_DIFFERENCE; resultP->X_add_number += right.X_add_number; clean_up_expression(resultP); } else { /* Not +. */ if (resultP->X_seg == SEG_UNKNOWN || right.X_seg == SEG_UNKNOWN) { resultP->X_seg = SEG_PASS1; need_pass_2 = 1; } else { resultP->X_subtract_symbol = NULL; resultP->X_add_symbol = NULL; /* Will be SEG_ABSOLUTE. */ if (resultP->X_seg != SEG_ABSOLUTE || right.X_seg != SEG_ABSOLUTE) { as_bad("Relocation error. Absolute 0 assumed."); resultP->X_seg = SEG_ABSOLUTE; resultP->X_add_number = 0; } else { switch (op_left) { case O_bit_inclusive_or: resultP->X_add_number |= right.X_add_number; break; case O_modulus: if (right.X_add_number) { resultP->X_add_number %= right.X_add_number; } else { as_warn("Division by 0. 0 assumed."); resultP->X_add_number = 0; } break; case O_bit_and: resultP->X_add_number &= right.X_add_number; break; case O_multiply: resultP->X_add_number *= right.X_add_number; break; case O_divide: if (right.X_add_number) { resultP->X_add_number /= right.X_add_number; } else { as_warn("Division by 0. 0 assumed."); resultP->X_add_number = 0; } break; case O_left_shift: resultP->X_add_number <<= right.X_add_number; break; case O_right_shift: resultP->X_add_number >>= right.X_add_number; break; case O_bit_exclusive_or: resultP->X_add_number ^= right.X_add_number; break; case O_bit_or_not: resultP->X_add_number |= ~ right.X_add_number; break; default: BAD_CASE(op_left); break; } /* switch (operator) */ } } /* If we have to force need_pass_2. */ } /* If operator was +. */ } /* If we didn't set need_pass_2. */ op_left = op_right; } /* While next operator is >= this rank. */ return(resultP->X_seg); } /* expr() */ /* * get_symbol_end() * * This lives here because it belongs equally in expr.c & read.c. * Expr.c is just a branch office read.c anyway, and putting it * here lessens the crowd at read.c. * * Assume input_line_pointer is at start of symbol name. * Advance input_line_pointer past symbol name. * Turn that character into a '\0', returning its former value. * This allows a string compare (RMS wants symbol names to be strings) * of the symbol name. * There will always be a char following symbol name, because all good * lines end in end-of-line. */ char get_symbol_end() { register char c; while (is_part_of_name(c = *input_line_pointer++)) ;; *--input_line_pointer = 0; return (c); } unsigned int get_single_number() { expressionS exp; operand(&exp); return exp.X_add_number; } /* * Local Variables: * comment-column: 0 * fill-column: 131 * End: */ /* end of expr.c */